This isn't exactly true. There's broiler feed which is generally high protein meant for fast growth in meat birds, and then there's grower which may or may not have more protein than layer (usually does) but does not have extra calcium. Every manufacturer uses terminology differently which further confuses things.
Most grower feed is suitable for layers (with calcium supplemented on the side) or as an all-flock type feed. Higher protein can be desirable in many cases as well as birds can exhibit certain bad behaviors if protein level is too low.
My flock gets half grower, half layer - so that slightly bumps up the protein % they get and also drops the calcium % (as I have some birds that are very sporadic layers).
